Effect of polysaccharides on gelatinization and retrogradation of wheat starch

Abstract

We employed differential scanning calorimetry and X-ray powder diffraction to determine the effect of tea polysaccharide (TPS) and carboxymethyl cellulose (CMC) on the gelatinization and retrogradation behavior of wheat starch (WS) gels. The total WS concentration of the gels was 35 wt%; WS/polysaccharide mixing ratios were 10/0, 9.9/0.1, 9.8/0.2, 9.7/0.3, 9.6/0.4, and 9.5/0.5. As the polysaccharide level was increased, the onset temperature, conclusion temperature and enthalpy of starch melting also increased. Samples blended with CMC exhibited higher gelatinization parameters than TPS mixtures at the same concentration. Upon reheating the starch samples after storage at 4 °C, we found that the glass transition temperature and retrogradation ratio decreased with increasing polysaccharide ratio and increased with the duration of storage. As the concentration of polysaccharide was increased, the endothermic enthalpy gradually decreased for the WS/TPS system and slightly increased for WS/CMC. After 20 days of storage at 4 °C, the degree of crystallization in the WS/TPS system was significantly lower than in the WS/CMC system. Avrima equation analysis revealed that the retrogradation rate of the control was eight times higher than samples containing 5% TPS and two times higher than samples containing 5% CMC. The overall results demonstrated that the inhibitory effect of TPS was greater than that of CMC under the same conditions.